Re: How to get Nvidia geforce 420M working?
If you need the most recent nvidia drivers for Lucid or Maverick (and have not messed around with trying to manually installing them from nvidia.com), you can get them by adding x-swat to your repositories http://www.ubuntuupdates.org/ppas/27
If you have not activated nvidia drivers yet, go to System > Administration > Additional Drivers (or Hardware Drivers in Lucid), "activate" nvidia, and reboot.
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
If you already activated nvidia earlier, just open Synaptic, type nvidia in Quick search, and reinstall nvidia-current, nvidia-settings, and nvidia-current-modaliases. Then reboot.
i5 650 3.2 GHz, 8 GB, nvidia GTX 750 Ti, 32" 1080p | i7-4700MQ, 8 GB, Intel HD 4600/nvidia GTX 765M, 15.6" 1080p | etc.